Melissa,
You really don't need much for the dog on board. As far as aspirin goes, a 27 lb dog would get about 1/2 a regular aspirin twice daily. You want to be careful using it though. Dogs can get gastrointestinal ulcerations and bleeding with long term use. I tell people to use it for no more than 3 days without stopping for a day or two. Frankly, if the dog needs it for more than a couple of days you should find out why. There are better drugs for long term anti inflammatory use than aspirin.
Since you can't slap a Band-Aid on a dog if it gets a cut foot, I'd bring along some rolled guaze and some tape on a roll in case you need to temporarily bandage a cut.
The only other drugs you might want can usually be found in the human medical kit. Maybe some neosporin antibiotic ointment. Immodium 2mg...should the dog (or its master) get diarrhea. A dog of 27 pounds would get 1 tablet twice daily. Perhaps some Pepcid, if the dog is throwing up some. One tablet a day should suffice...again on a temporary basis. Benedryl 25mg...if the dog gets a bee sting or some allergic reaction. 1 capsule twice daily should do it..but it will make the dog groggy. If any of these things persist, you'll have to go ashore and have it checked out.
Make sure you give the dog fresh water often. Especially if its hot. Some people have trained their pets to "relieve themselves" in specified areas aboard the boat. Other dogs just won't handle that. Which means you will have to go ashore (via dinghy if needs be) 2 to 3 times a day.
Most pets do pretty well once they get used to it. Oh yes...dogs can get sunburned an overheated so make sure there is a place in the shade somewhere for Fido to go to. The main thing to remember, if the dog isn't right for a couple of days, have him checked out.
Hope this helps
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